Jefferson County, MO Environmental Rules: Erosion Control (2026)

190 of the county code, bars anyone, including utility crews, from beginning a land disturbance activity such as mechanized clearing or grading without a County land disturbance permit. The permit threshold is 5,000 square feet: any new or redevelopment project disturbing that much ground or more must obtain a permit from the Director of Public Works before work starts, and other construction permits for the same site are held up until it is issued. Between 5,000 square feet and one acre, the county does not usually require a permanent stormwater best management practice such as a swale, ditch or check dam unless the Director determines one is needed or the project is part of a larger common plan of development.

At one acre or more, or for smaller phases of a larger common plan, the applicant must design and install structural or non-structural BMPs that address long-term stormwater runoff quality. The permit fee is tiered by acreage: through the end of 2025 it runs from $250 for sites under an acre up to $2,750 plus $10 per acre over 25 acres for the largest sites, and a new fee schedule starting January 1, 2026 raises the base fees to $300 through $3,750 plus $10 per acre over 25 acres, with the fee covering plan review and a set number of inspection hours.

A handful of activities are exempt, including disturbances under 5,000 square feet outside a common plan of sale, ordinary crop farming and tilling, permitted quarry operations, and emergency work needed to protect life or property, though the Director can revoke an exemption if erosion controls are not actually being used.